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Electromagnetism · Radar research
Research activities

Next Generation Hardware

Metasurfaces - Phased antenna arrays - Radiofrequency electronics

Abstract.
Next Generation Hardware

Maxwell’s equations 

Four fundamental equations that describe how electric and magnetic fields are generated and how they propagate as electromagnetic waves.

Novel radiant/reflective elements

Newly designed structures or materials that control how electromagnetic waves are emitted or reflected.

Advances in radar and microwave technology are continually expanding what is possible through innovative approaches to electromagnetic system design.

The progress in technology has been pushing the frontiers of what is feasible thanks to new and ingenuous solutions that had been proposed, particularly in the radar technology domain. Via the taming of the Maxwell’s equations for radiative structures and guided propagation, from optimization or enhancement of radio frequency architecture to novel radiant/reflective elements, SONDRA is always present in this effort of proposing and implementing the next generation of radar and microwave systems.
I.
Chapter 1
Margin notes

Metamaterials

Artificial materials designed to have properties not found in nature, used to control electromagnetic waves.

Reflectarray antenna

A type of antenna that reflects and shapes waves to form a directed beam.

Transmitarray antenna

An antenna that transmits and reshapes electromagnetic waves to form a controlled beam.

Metasurfaces

Metamaterials and metasurfaces enable precise control of electromagnetic waves through engineered subwavelength structures.

The concept of metamaterials emerged as a way to knowingly engineer properties of artificial structures and adapt them to real-life applications. By creating spatial modulation (design at the wavelength scale) in a reflective surface, metasurface, it becomes possible to perform wavefront transformations such as anomalous reflection and transmission. Thus, electrically reconfigurable metasurfaces find their application in antennas and have been used, in particular, to improve performances of reflectarray and transmitarray antennas.

II.
Chapter 2
Margin notes

Polarization

The orientation of the wave’s oscillation (how the wave “vibrates”).

Axial ratio

A measure of how circular or linear the polarization is; used to judge polarization quality.

Phased antenna array

A group of antennas that work together, adjusting signal timing to steer the beam electronically.

Phased antenna arrays

Radar systems use controlled electromagnetic waves and phased antenna arrays to detect and characterize targets while reducing clutter.

The radar systems were first used for the detection and distance estimation of objects. Progress in the understanding of the electromagnetic waves allowed to control their direction an intensity while keeping a high polarization purity (axial ratio) for wide frequency bandwidths. All these characteristics have to be taken into account while designing phased antenna arrays for radar applications for extracting the most of information of the targets (size, shape and electrical properties) while minimizing the influence of the clutter.
III.
Chapter 3
Margin notes

Purity (of signals)

The degree to which a signal is free from distortion or unwanted changes.

Radiofrequency electronics

Radar system performance relies heavily on maintaining signal quality throughout the entire radio-frequency processing chain.

The success of the radar systems depends strongly on the preservation of the purity (phase and linearity) of the emitted and received radio signals, during their amplification, filtering, modulation and demodulation, mixing, up to analog/digital conversion. All these stages besides noise and non-linearity limits need to be considered in the design of the RF front-end architecture, their elements and radiating elements.